5个常绿园林树种的夏季光合蒸腾特性  

Characteristics of Photosynthesis and Transpiration of Five Evergreen Tree Species in Summer

作　　者：薛雪[1,2] 李娟娟 郑云峰[4] 张金池[1,2] 庄家尧[1,2] 王鹰翔[1,2] 

机构地区：[1]南京林业大学水土保持与生态修复实验室,南京210037 [2]江苏省南方现代林业协同创新中心,南京210037 [3]迪士尼中国研究,上海200021 [4]国家林业局华东林业调查规划设计院,杭州310019

出　　处：《林业科学》2015年第9期150-156,共7页Scientia Silvae Sinicae

基　　金：国家自然科学基金项目(31170663);江苏省高等学校林学优势学科建设项目(164010641)

摘　　要：【目的】分析5个园林常绿绿化树种的夏季光合蒸腾日变化特征及其与环境因子的关系,以进一步研究城市园林植物的生理生态学特性,探讨其对城市环境的适应性及配置合理性,同时评价其生态功能,为城市园林绿化树种的选择和养护提供科学理论依据,以进一步改善城市热岛效应。【方法】本研究在2013年7月21—23日夏季典型晴朗天气,以上海地区5个常用的常绿绿化树种石楠、广玉兰、蚊母、香樟、桂花为研究对象,采用LI-6400XT光合作用仪测定各个树种的光合蒸腾生理生态指标和主要环境因子,并分析其相关性。【结果】5个常绿树种夏季Pn(净光合速率)日变化均为双峰型,具有明显的"光合午休"现象,分析主要为非气孔限制所致。石楠、桂花、广玉兰和蚊母的Tr(净蒸腾速率)日变化均呈双峰曲线,香樟呈单峰曲线;石楠Pn和Tr日均值显著大于其他4个树种,蚊母最小。石楠和蚊母WUE(水分利用效率)日均值较高。根据蒸腾光合特性的影响因子相关性分析,Pn与Gs(气孔导度)、Ci(胞间CO2浓度)、Tl(叶片温度)、PAR(光合有效辐射)和Ta(空气温度)呈显著正相关性,与RH(相对湿度)呈显著负相关性;Tr与Gs,Ci,PAR,RH,VPD(水汽压亏缺)和WUE呈显著正相关性。【结论】广玉兰和蚊母蒸腾速率较小,日均光合速率较低;蚊母水分利用效率较高,广玉兰较低,建议养护中适当采取遮光措施减弱光抑制;香樟蒸腾速率较大,水分利用效率较低,建议养护中加强遮荫、灌溉以降低其蒸腾失水。在夏季,石楠、香樟和桂花抗强光、高温能力优于蚊母和广玉兰;石楠、蚊母能更有效利用土壤水分,适应较干燥的环境气候。[Objective]In this study,the diurnal variation characteristics of photosynthesis and transpiration of five evergreen tree species in Shanghai were measured in summer to understand the physiological and ecological characteristics of urban main greening trees. This study investigated the tree species’adaptability to urban environment and rationality of spatial configuration,and evaluated the ecological function,in order to provide scientific-based reference for selection and maintenance of urban greening tree species for mitigating urban heat island effect.[Method]During July 21-23,2013 the typical hot and sunny summer days in Shanghai,five main urban evergreen tree species,including Photinia serrulata, Magndia grandiflora,Distylium racemosum,Cinnamomum campora,Osmanthus fragrans,were selected to measure the photosynthesis and transpiration variation and the surrounding environmental factors by using LI-6400 XT photosynthesis system. The measured parameters included net photosynthesis rate （ Pn ） , net transpiration rate （ Tr ） , stomatal conductance （Gs）,intercellular CO2 concentration （Ci）,leaf temperature （Tl）,vapor pressure deficit （VPD）, atmospheric CO2 concentration （Ca）,photosynthetic active radiation （PAR）,air temperature （Ta）,relative humidity （ RH） . The correlation analysis between measured parameters and environmental factors was conducted accordingly.[Result]The diurnal variation of Pn of the five tree species showed doubled-peaks curve and indicated “midday depression”at midday,which was mainly due to non-stomatal limitation. The diurnal variation of Tr of the measured trees showed doubled-peak curve besides C. campora that was with single-peak curve. The daily mean value of Pn and Tr of P. serrulata was significantly higher than the other four species,with D. racemosum the lowest. A significant positive correlation was found between Pn and Gs,Ci,Tl,PAR,Ta,while a significant negative correlation was found between Tr and Gs,Ci,PAR,RH,VPD,WUE. [Conclusion]T

关 键 词：常绿树种 日变化 光合特性 蒸腾速率 光合生理参数 

分 类 号：S718.51[农业科学—林学]